By
John Mathey on September 1st, 2009
In this article we will look at why we need to consider energy correction when producing frequency spectra and how we go about it. We will use a perfect, ’special case’ signal to keep the explanation as simple as possible. The signal we will use is periodic within the time record used to calculate the [...]
By
John Mathey on July 20th, 2009
Before we discuss the use of data windows, we should first remind ourselves of three basic properties of the FFT (Fast Fourier Transform) process.
First, energy information in signal must be preserved during transformation. That is, the energy measured on time signal must equal the energy measured on the frequency representation of that signal.
Second, an FFT [...]
By
Dr Colin Mercer on July 29th, 2003
Fourier analysis takes a signal and represents it either as a series of cosines (real part) and sines (imaginary part) or as a cosine with phase (modulus and phase form). As an illustration we will look at Fourier analysing the sum of the two sine waves
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